Enhanced Measurement Gap Configuration Support for Positioning

1. A method implemented by a base station configured to serve a wireless device in a serving cell of a wireless communication system on a serving frequency, the method comprising: obtaining information that indicates one or more non-serving frequencies on which the wireless device is to perform one or more positioning measurements that are to be used for determining the wireless device's geographic position; and for at least one non-serving frequency indicated by the information, configuring a measurement gap during which the wireless device is to perform a corresponding positioning measurement to occur during a period of time in which a neighboring cell transmits a positioning reference signal over that non-serving frequency.

2. The method according to claim 1 , wherein said obtaining comprises receiving at least some of the information within a request from the wireless device requesting that the base station configures one or more measurement gaps during which the wireless device is to perform the one or more positioning measurements on the one or more non-serving frequencies.

3. The method according to claim 1 , wherein said obtaining comprises receiving at least some of the information via control signaling from a positioning node of the wireless communication system.

4. The method according to claim 3 , wherein said control signaling is received from the positioning node using a Long Term Evolution (LTE) Positioning Protocol Annex, or using an LTE Positioning Protocol extension.

5. The method according to claim 1 , wherein said obtaining comprises obtaining at least some of the information by inspecting higher layer communications transmitted between the wireless device and a positioning node of the wireless communication system.

6. The method according to claim 5 , wherein said higher layer communications are transmitted between the wireless device and the positioning node using an Long Term Evolution (LTE) Positioning Protocol.

7. The method according to claim 1 , further comprising, for at least one other non-serving frequency indicated by the information, configuring a measurement gap during which the wireless device is to perform a corresponding positioning measurement to occur during a period of time in which a neighboring cell transmits a signal other than a positioning reference signal over that non-serving frequency.

8. The method according to claim 1 , wherein the information also indicates the periods of time during which one or more neighboring cells transmit respective positioning reference signals on the one or more non-serving frequencies.

9. The method according to claim 8 , wherein the information indicates the period of time during which any given neighboring cell transmits a positioning reference signal as an offset from the period of time during which the serving cell transmits a positioning reference signal, or as an offset from the period of time during which a reference cell transmits a positioning reference signal, wherein positioning measurements performed on the positioning reference signal transmitted by the reference cell serve as a reference for positioning measurements performed on positioning reference signals transmitted by other cells.

10. The method according to claim 9 , wherein the information indicates said offset as either a subframe offset, a System Frame Number (SFN) offset, or a positioning reference signal (PRS) subframe offset.

11. The method according to claim 1 , wherein the information also identifies at least one neighboring cell on which the wireless device is to perform the one or more positioning measurements.

12. The method according to claim 1 , wherein the information indicates one or more non-serving frequencies selected from two or more different possible non-serving frequencies.

13. The method according to claim 1 , wherein said one or more positioning measurements comprise inter-frequency, inter-RAT, or inter-band measurements.

14. The method according to claim 1 , wherein the wireless device requires one or more measurement gaps in order to perform corresponding ones of said one or more positioning measurements on the one or more non-serving frequencies.

15. The method according to claim 1 , wherein said one or more positioning measurements comprise one or more timing measurements.

16. The method according to claim 15 , wherein said one or more timing measurements comprise: one or more Reference Signal Time Difference (RSTD) measurements for Observed Time Difference of Arrival (OTDOA); one or more Receive-Transmit (Rx-Tx) time difference measurements; and one or more Timing Advance (TA) measurements.

17. A method implemented by a wireless device in a wireless communication system, the wireless device served in a serving cell by a base station on a serving frequency, the method comprising: obtaining information that indicates one or more non-serving frequencies on which the wireless device is to perform one or more positioning measurements that are to be used for determining the wireless device's geographic position; and transmitting to the base station the information and a request for the base station to configure one or more measurement gaps during which the wireless device is to perform the one or more positioning measurements.

18. The method according to claim 17 , wherein said transmitting comprises including the obtained information in the request.

19. The method according to claim 17 , wherein the serving cell implements a serving radio access technology (RAT), wherein said obtaining comprises receiving, via at least one of a higher-layer protocol extension and user plane communications, said information in conjunction with a request for the wireless device to use said information to perform said positioning measurements on one or more neighboring cells that implement one or more non-serving RATs.

20. The method according to claim 17 , further comprising: receiving a response from the base station including information identifying when the one or more measurement gaps have been configured to occur; and performing the one or more positioning measurements on the one or more non-serving frequencies during the one or more measurement gaps, performing at least one positioning measurement by measuring a positioning reference signal transmitted from a neighboring cell during a corresponding measurement gap using a corresponding non-serving frequency.

21. The method according to claim 17 , wherein the information also indicates the periods of time during which one or more neighboring cells transmit respective positioning reference signals on the one or more non-serving frequencies.

22. The method according to claim 21 , wherein the information indicates the period of time during which any given neighboring cell transmits a positioning reference signal as an offset from the period of time during which the serving cell transmits a positioning reference signal, or as an offset from the period of time during which a reference cell transmits a positioning reference signal, wherein positioning measurements performed on the positioning reference signal transmitted by the reference cell serve as a reference for positioning measurements performed on positioning reference signals transmitted by other cells.

23. The method according to claim 22 , wherein the information indicates said offset as either a subframe offset, a System Frame Number (SFN) offset, or a positioning reference signal (PRS) subframe offset.

24. The method according to claim 17 , wherein the information also identifies at least one neighboring cell on which the wireless device is to perform the one or more positioning measurements.

25. The method according to claim 17 , wherein the information indicates one or more non-serving frequencies selected from two or more different possible non-serving frequencies.

26. The method according to claim 17 , wherein said one or more positioning measurements comprise inter-frequency, inter-RAT, or inter-band measurements.

27. The method according to claim 17 , wherein the wireless device requires one or more measurement gaps in order to perform corresponding ones of said one or more positioning measurements on the one or more non-serving frequencies.

28. The method according to claim 17 , wherein said one or more positioning measurements comprise one or more timing measurements.

29. The method according to claim 28 , wherein said one or more timing measurements comprise: one or more Reference Signal Time Difference (RSTD) measurements for Observed Time Difference of Arrival (OTDOA); one or more Receive-Transmit (Rx-Tx) time difference measurements; and one or more Timing Advance (TA) measurements.

30. A method implemented by a network node in a wireless communication system, the system including a base station configured to serve a wireless device in a serving cell of the system on a serving frequency, the method comprising: obtaining information that indicates one or more non-serving frequencies on which the wireless device is to perform one or more positioning measurements during one or more configured measurement gaps on one or more positioning reference signals transmitted by one or more neighboring cells, wherein the one or more positioning measurements are to be used for determining the wireless device's geographic position; and sending the obtained information to the base station.

31. A method implemented by a network node in a wireless communication system, the system including a base station configured to serve a wireless device in a serving cell of the system on a serving frequency, the method comprising: obtaining information that indicates whether or not the base station is capable of configuring one or more measurement gaps during which the wireless device can perform one or more positioning measurements on one or more non-serving frequencies, wherein the one or more positioning measurements are to be used for determining the wireless device's geographic position; and if the base station is capable of configuring the one or more measurement gaps, sending a request to the wireless device requesting that the wireless device perform the one or more positioning measurements with respect to at least one neighboring cell.

32. A base station configured to serve a wireless device in a serving cell of a wireless communication system on a serving frequency, the base station comprising a measurement gap configuration circuit configured to: obtain information that indicates one or more non-serving frequencies on which the wireless device is to perform one or more positioning measurements that are to be used for determining the wireless device's geographic position; and for at least one non-serving frequency indicated by the information, configure a measurement gap during which the wireless device is to perform a corresponding positioning measurement to occur during a period of time in which a neighboring cell transmits a positioning reference signal over that non-serving frequency.

33. A wireless device configured to be served in a serving cell of a wireless communication system by a base station on a serving frequency, the wireless device comprising: a radio interface configured to wirelessly communicate with the base station over radio resources; and one or more processing circuits configured to: obtain information that indicates one or more non-serving frequencies on which the wireless device is to perform one or more positioning measurements that are to be used for determining the wireless device's geographic position; and transmit to the base station, via the radio interface, the information and a request for the base station to configure one or more measurement gaps during which the wireless device is to perform the one or more positioning measurements.

34. A network node in a wireless communication system, wherein the system includes a base station configured to serve a wireless device in a serving cell of the system on a serving frequency, and wherein the network node comprises: a communications interface configured to communicatively couple the network node to the base station and the wireless device; and one or more processing circuits configured to: obtain information that indicates one or more non-serving frequencies on which the wireless device is to perform one or more positioning measurements during one or more configured measurement gaps on one or more positioning reference signals transmitted by one or more neighboring cells, wherein the one or more positioning measurements are to be used for determining the wireless device's geographic position; and send the obtained information to the base station via the communications interface.

35. A network node in a wireless communication system, wherein the system includes a base station configured to serve a wireless device in a serving cell of the system on a serving frequency, and wherein the network node comprises: a communications interface configured to communicatively couple the network node to the base station and the wireless device; and one or more processing circuits configured to: obtain information that indicates whether or not the base station is capable of configuring one or more measurement gaps during which the wireless device can perform one or more positioning measurements on one or more non-serving frequencies, wherein the one or more positioning measurements are to be used for determining the wireless device's geographic position; and if the base station is capable of configuring the one or more measurement gaps, send via the communications interface a request to the wireless device requesting that the wireless device perform the one or more positioning measurements with respect to at least one neighboring cell.